Centrifugal guided speed responsive device



July 24 1951 s. s. BROWN 2,561,560

CENTRIFUGAL GUIDED SPEED RESPONSIVE DEvIcE Filed Oct. 16, 1947 3Sheets-Sheet 1 INVENTOR STEFFEN 5. BROWN BY 4 www www ATTORNEYS v July24, 1951 s. s. BROWN 2,561,560

CENTRIFUGAL GUIDED SPEED RESPONSIVE DEVICE Filed Oct. 16, 1947 5Sheets-Sheet-Z NVENTOR STEFFEN S. BROWN July 24, 1951 s. s. BROWN2,561,560

CENTRIFUGAL GUIDED SPEED RESPONSIVE DEVICE Filed Oct. 16, 1947 5Sheets-Sheet 3 5511 Tg. ,1E

INVEN'roR STEFFE N 5. BROWN ATTURNEYS Patented July 24, 1951 CENTRIFUGALGUIDED SPEED RESPONSIVE DEVICE Steffen S. Brown, Dayton, Ohio, assignorto The Brown-Brockmeyer Company, Dayton, Ohio, a

corporation of Ohio Application October 16, 1947, Serial No. 780,291

This invention relates to switches and to actuators therefor, andparticularly to a centrifugal vactuator for a switch.

In the construction of many devices, such as electric motors, it iscommon to include a switch `which operates in response to apredetermined motor speed for opening a circuit. Switches of this typeare employed in connection with split phase motors for opening thestarting winding Acircuit at a predetermined motor speed to eliminatethe loss of power in the starting winding and to permit the motor tooperate as a pure repulsion motor when running under load.

The particular object of this invention is to provide an improved typeof centrifugal actuator for a switch of this nature.

Another object is to provide a centrifugal switch actuator which is verysimple to assemble and which is therefore inexpensively mounted in amotor.

A still further object is the provision of a centrifugal actuator inwhich the several parts can easily be manufactured by mass productionmethods.

A still further object is the provision of a centrifugal switch actuatorwhich is substantially fully enclosed thereby protecting the mechanismof the actuator from dirt.

A still further object is the provision of a centrifugal actuator forswitches and the like which is unusually small and which therefore canbe mounted in a small space.

In the operation of electric motors having centrifugal switches thereinit is necessary that the switch open and close sharply. It is alsoimportant that once open the switch will remain open until the motorspeed falls to a predetermined value.

Accordingly, it is a still further object of this invention to provide acentrifugal actuator for a switch which has a precision snap action andwhich does not flutter or hunt when the motor speed is reduced due toheavy loads being imposed thereon.

These and other objects and advantages will become more apparent uponreference to the following description taken in connection with theaccompanying drawings in which:

Figure 1 is a vertical section taken along the axis of an electric motorhaving mounted therein a centrifugal switch and actuator according tothis invention;

Figure 2 is an enlarged sectional View taken through the switch actuatorand showing the internal construction thereof;

9 Claims. (Cl. 264-17) Figure 3 is a transverse section through theactuator and is indicated by the line 3--3 on Figure 2;

Figure 4 is another transverse section through the actuator and isindicated by the line 4 4 on Figure 2 and shows the switch device whichis operated by the actuator;

Figure 5 is a side view of the switch mechanism of Figure 4;

Figure 6 is a section indicated by the line 6--6 on Figure 5 and showsthe relative positioning of the contacts of the switch;

Figures '7 and 8 are views of the weights in the centrifugal actuator;

Figure 9 is a view of one of the cup shaped members in which the weightsare positioned in the assembled actuator;

Figure 10 is a perspective View of a washer which is employed in theactuator for retaining the weights in their proper relative position;and

Figures 11 and 12 are sectional views through the switch and actuatorshowing the parts in different operative positions.

Referring to the drawings, in Figure l there is illustrated a typicalelectric motor consisting of a stator l0 having windings l2 thereinwhich includes starting and running windings.

The stator is mounted in a motor frame I4 which includes the end coversi6 and I8 secured to the motor frame lin any well known manner. Each ofthe motor end covers includes bearings 20 which journal a shaft 22 thatsupports a rotor 24 within the stator IU.

The shaft 22 may also carry a fan 26 for circulating cooling air withinor through the motor frame if desired.

The end. cover I8 may have mounted therein a condenser as at 28 which isin circuit with the starting winding and which is to be employed duringthe starting period of the motor,

The circuit through the condenser 28 and the starting winding of thestator is established through a switch mounted at 30 in the end coverI6.

This switch is better seen in Figures 4, 5 and 6 wherein it will be seento comprise a mounting panel 32 of insulating material which is securedto the cover I6 and which has secured thereto the spring arm 34. The arm34 is riveted to the panel at 36 and has a connection made therewith bythe wire 38. The other end of the arm 34 carries a contact 40 which iscontinuously urged away from the contact 42 on the panel 32 by theresilienci7 of the arm 34. A stop bracket 44 is provided for limitingthe movement ot the contact 4d away from the contact 42.

Iih 4i! and 42 are normally mainf- .ent by the pressure on the arm 34 ofthe flange 45 of a cup shaped member 48 which lorlns a part of theactuator assembly generally indicated at 5i] in Figure l. and shown morein. detail in Figure 2.

'.iiie cup shaped member 48 has an inner sleeve which is slidablysplined to the shaft 22 by the spline means 54 and which is continuously urged toward the left in Figure 2 by the compression spring 55.The compression spring 56 bears betw the member 48 and a washer 58, thesaid washer being retained in position on the shaft by the snap ring 66.

Also mounted on the shaft 22 is a second cup shaped member 62 whichopens toward the member 48 and which telescopes therewith as at 64. Themember i2 is retained in position on the shaft 22 by the snap ring 66.

Mounted within, the cup shaped members 48 and 62 are the Oshaped weights68 which have their adjacent faces abutting as at l0. It will be obviousin Figure 2 that the Weights engage the members at the bottoms of therecesses therein and that theJ outer surfaces of the weights aredivergent with the walls of the cup shaped members toward the open sidesthereof. The weights, together with the members in which they are.mounted thus form a toggle like arrangement.

The adjacent faces of the weights are provided with spherical.protuberances and recesses indicated at 12, and best seen in Figures '7and r8, and which provide a pivot axis about which the weights may pivotrelatively.

mentioned before the weights are substantially C-shaped, as shown inFigure 8, and the faces ol the said weights below the pivot axis formedby the protuberances and recesses 12 are divergent as will be seen fromthe dotted line indicated at 14 in Figure 2.

'For uniform action of the actuator there are preferably two sets ofweights therein. This provides for an actuating thrust on each side ofthe actuator members and prevents the binding thereof on the shaft 22.

For maintaining the two sets of Weights in their proper relativepositions each of the said weights has a projection extending from the.back thereof at E6 which. is receivable in a notch of a washer 8f).

This washer is illustrated in Figure 1G and it will be observed that thenotches so disposed therein that the two weights in each member will beretained at exactly 180 degrees from each other.

The tips of the G--shaped weights are also provided with projections asat 82 which projections are shorter in height than the projections T6 bythe thickness of the washer S0. The projections 32 thereby provide stopsfor stopping the weights in their innermost position.

It will be evident upon reference to Figure 2 that the center of gravityof each of the several weights GB is well within the point about whichit pivots on its associated cup shaped member. The last mentioned pointsare indicated n Figure 2 at 84 and are the points of engagement of theprojections l5 with the cor-t ners of the members. These points, orlines, form the point axes for the several Weights when they throw outin the i'nembers due to centrifugal :forces acting thereon.

Due to the relative location of the center of gravity of each weight andthe point about which it pivots in its cup shaped member, the action ofthe switch is extremely rapid because once the weightsconunence to move,not only is the moment arm of the weight thereof about the said pivotpoint increased, but the center of gravity is moved out further from thecenter of the shaft and thereby increases the amount of centrifugalforce. Thus, the movement of the weights outwardly in the actuator is inthe nature of a snap action and having moved out, the weights willremain, in their outermost position until the speed of the motor hasbeen reduced to substantially less than that which was required to throwthem out.

In operation, rotation of the shaft 22 will drive the member 48 directlythrough the spline means at 54. When rotation of the actuator commencesthe members 48 and 62 thereof are urged together by the spring 56 andthis also maintains the weights in their inner positions as shown inFigure 2.

When the speed of the shaft 22 has reached a certain value the weights68 will commence to move outwardly, pivoting in the members 48 and 62 atthe point B4, and relative to each other about the pivot axes dened bythe protuberances and recesses 12.

As soon as outward movement of the Weights has commenced, the increasingradial distance outwardly of the centers of gravity thereof, and theincreasing moment arm through which the centrifugal force on the weightsact, causes the said weights to snap into their outermost position.

The movement outwardly of the weights increases their elective axiallength within the actuator due to the toggle arrangement of the saidweights. This will bring about movement of the member 4B rightwardly andpermit the spring arm 34 to disengage the contacts 40 and 42.

It will be noted that at this time there are no rotating parts inengagement with stationary parts. Thus, all wear on the flange of theactuator member 48 and the arm 34 will take place in the relativelybrief period that is required for the motor to come up to speed. Thispromotes long life of the actuator and quiet operation of the motor.

It will be apparent that engagement of the weights 68 by the washers 80prevents the circumierential displacement of the Weights in each memberdue to acceleration thereof during the starting or stopping of the motorshaft.

Relative displacement of the weights in one member relative to those inthe other members is prevented by the interengagement of the weightsthrough the aforementioned protuberances and recesses 12.

It will be understood that this invention is susceptible to modificationin order to adopt it to different usages and conditions and,accordingly, it is desired to comprehend such modications within thisinvention as may fall within the scope of the appended claims.

I claim:

l. In a centrifugal actuator, a pair of members mounted on a shaft andadapted for rotation therewith about a predetermined axis, each memberhaving side and circular bottom walls integrally formed to denne acorner, said members being spaced apart, said side wall of each memberextending toward the other thereof dening a substantially enclosedweight receiving space, a. p

pair of weights between said members one plvotally abutting the cornerof one member and the other pivotally abutting the corner of the othermember, said weights also abutting each other, said weights forming a,pivot axisvtherebetween at their point of abutment, and means urgingsaid members toward each other.

2. In a centrifugal actuator, spaced members each having side and bottomwalls integrally vformed to define a corner, said side wall of eachmember extending toward the other thereof dening a substantiallyenclosed weight receiving space, a weight positioned Within each memberin said space and in abutting pivotal engagement with the corner of themember in which it is positioned, yielding means urging said memberstoward each other and holding the weights in abutting engagement witheach other, and interfitting parts on the weights for forming an axisfor relative pivoting movements therebetween, said axis being inwardlyof the engagement of the weights and corners, the arrangement being suchthat relative pivoting movements of said weights outwardly will movesaid members apart.

3. In a centrifugal actuator, a pair of members adapted for beingmounted in spaced relation on a shaft and rotated therewith, saidmembers each having side and bottom walls defining a corner, said sidewall of each member extending toward the other thereof defining asubstantially enclosed weight receiving space, weights positioned insaid space and inwardly of said corners, one of said weights being inabutting pivotal. engagement with the corner of one member and anotherof said Weights being in abutting pivotal engagement with the corner ofthe other member, yielding means urging said members toward each otherandholding said weights in abutting engagement with each other, andintertting parts on said weights forming a pivot axis for relativepivoting movements therebetween, said axis being inwardly of theaforementioned corners on said members, the arrangement being such thatoutward movement of said weights will urge said members apart and meansfor preventing relative circumferential movement between each weight andits member.

4. In a centrifugal actuator, a pair of spaced cup-shaped members eachhaving side and bottom walls defining a corner, said side wall of eachmember extending toward the other thereof defining a substantiallyenclosed Weight receiving space, a C-shaped weight positioned withineach member in said space and in abutting pivotal engagement with thecorner of the member in which it is positioned, yielding means urgingsaid members toward each other and holding said weights together, andabutment means on said weights forming an axis for relative pivotingmeans thereof in response to a predetermined centrifugal force actingthereon, said axis being substantially nearer to the center of saidactuator than the aforementioned corner of said members, the opposedfaces of said weights each being formed of two planar areas at angles toeach other so that one corresponding pair of said areas are contiguousfor each of the inner and outer positions of said weights while theother pair thereof are divergent.

5. In combination with a shaft, a rst cu-pshaped member mounted on saidshaft, a second cup-shaped member slidably mounted on said shaft, saidmembers each having side and bottom walls dening a corner, a weightpositioned within each member, a projection on a corner of each weightand abuttingly pivotally engaging the corner of its associated member,resilient means urging said members toward each other and maintainingsaid weights together, intertting abutment means comprising aprotuberance on one weight and a recess in the other' lmounted inv eachof said members, a projection on a corner of each of weights abuttinglypivyotally engaging its associated member at the corner between the sideand bottom walls thereof, resilient means for urging said splined membertoward said cup-shaped member and for urging said weights together,interengaging abutment means on said weights for relative pivotingmovements between one pair of weights and the other pair of weights,said axis being disposed substantially nearer to the axis of said shaftthan the aforementioned corners, said weights being operable when thrownoutwardly from said shaft by centrifugal force to move said membersapart and when moved inwardly toward said shafts to permit said membersto move toward each other, and means in said members preventing relativecircumferential movement between each weight and its member.

'7. In a centrifugal actuator, a pair of spaced members mounted on ashaft and adapted for rotation therewith about a predetermined axis,said members each being of cup-shape and having side and bottom wallsdefining a corner, said side wall of each member extending toward theother thereof defining a substantially enclosed weight receiving space,a pair of weights in said space, one of said weights being in abuttingpivotal engagement with the corner of one member and another of saidweights being in abutting pivotal engagement with the corner of theother member, interiitting parts on said weights for forming an axis forrelative pivoting movements therebetween whereby pivoting movement ofsaid weights outwardly will move said members apart and meansresiliently urging said members toward each other and means including anelement in each member adapted to receive a portion of one of theweights to prevent relative circumferential movement between each weightand its member.

8. In a centrifugal actuator, a pair of spaced members mounted on ashaft and adapted for rotation therewith about a predetermined axis,said members each being of cup-shape and having side and bottom wallsdefining a corner, said side wall of each member extending toward theother thereof defining a substantially enclosed weight receiving space,a pair of weights in said space, one of said weights being in abuttingpivotal engagement with the corner of one member and the other of saidweights being in abutting pivotal engagement with the corner of theother member, and interfitting means comprising a protuberance on oneweight and a recess in the other weight for forming an axis for relativepivoting movements therebetween, and means urging said members towardeach other.

9. In combination: a shaft, a member slidably splined to said shaft andhaving an annular recess therein, a cup-shaped member mounted on saidshaft having its open side facing said recess and teiescoping saidrecessed member, each of said members having a side and circular bottomwall formed integral to define a cerner, a pair of C-shaped Weightsmounted in each of said members, a projection on a corner of each weightabuttingly pivotally engaging its associated member at its corner,resilient means for urging said splined member toward said cup-shapedmember for urging said weights together, interengaging abutment means onsaid weights for relative pivoting movements between one pair of Weightsand the other pair of weights, said Weights being operabie when thrownoutwardly from said shaft by centrifugal force to move said membersapart and when moved inwardly toward said shaft to permit said membersto move toward each other, and means in said members preventing relativecircumferential movement between said each weight and` its member, saidlast named means including a washer element carried by each member andhaving openings therein through which the projection on the corner ofeach weight extends.

STEFFEN S. BROWN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS

